Concrete and hydraulic cement



106. COMPOSITIONS,

9 OCOATING OR PLASTIC.

Patented Feb. 25, 1936 UNITED STATES PATENT OFFICE CONCRETE ANDHYDRAULIC CEMENT George R. Tucker, deceased, late of North Andover,Ma'ssj'by Charles W. Tucker, adminis- No Drawing. Application December5, 1934, Serial No. 756,082

17 Claims.

T'his invention relates to concrete and the hydraulic cement from whichit is prepared, and comprises the introduction into the concrete orcement of a small quantity of a hydroxy-alkyl v amine or a salt orderivative thereof, all as more fully hereinafter described and claimed.

An object of the invention is to increase the compressive strength ofhardened concrete beyond that which can be obtained from any givenmixture of hydraulic (e. g. ordinary Portland) cement, re ates, andwater. Another 051cc? is to reduce iEe amount 0 y aulic cement requiredunder any fixed set of conditions to produce a unit volume of hardenedconcrete of assigned compressive strength, or conversely, to increasethe volume of hardened concrete of specified strength which can beobtained under any given set of conditions from a unit weight ofhydraulic cement. Yet another object is to provide a substance whichwhen introduced into concrete in small quantity will improve the qualitythereof. Still other objects and advantages of the invention will becomeapparent with its more detailed description.

We have discovered that the compressive strength of hardened concretemay be increased, or that the amount of hydraulic cement essential underany given set of conditions to produce a unit volume of hardenedconcrete of assigned strength may be reduced, by introducing into theconcrete 2. suitable quantity of a water-soluble h drox -alk l amine ora salt or derivative thereoi We have found that the ethanol aminespossess special advantages and of the available compounds, triethanolamine is the most effective.

The commercial product consisting largely of triethanol amine togetherwith smaller quanme'so e primary and secondary compounds, is muchcheaper than the pure compound and is 40 very satisfactory. We havefound, however, that in place of triethanol amine we may effectivelyemploy other hydroxy-alkyl amines, for example, diet-hancl amine ortri-isopropanol amine.

or e genera purm it makes no difference whether the hydroxy-alkyl aminesare employed in-the form of their free bases or in the form of salts.Moreover, when we use the general term hydroxy-alkyl amine, or aspecific name of a member of this class, i. e. triethanol amine, we meannot only the pure chemical compound or one of its salts, but anychemical compound or combination which will give rise to the desiredhydroxy-alkyl amine under the conditions of use of the same. Further, asalt of the hydroxy-alkyl amine as it is used n pplication is to beconstrued as being either the git of the hydroxy-alkyl amine with aninorganic acid, or w .1 i w. id. Thus, for some purposes we employ suchsalts as a hydroxy-allgvl ammonium chloride or the sulphate, 'while in 0other cases we have found it particularly advantageous to use salts of.organic acids, as for exmple, a. m mmni wgl mpersin agent described byGeorge R. c er in n '1 i edNovember 10 Wn this latter case hecombination gives greatenworkabillty to the cement-concrete mix as wellas an increase in strength in the hardened concreter Inasmuch as thefree amines are generally of fiuid or viscous consistency, how- 15 ever,it is desirable to use the solid salts whenever it is wished to treatdry hydraulic cement in accordance herewith.

In general, we have found that one part of hydroxy-alkyl amine, or a.quantity of salt which 20 contains an amount of chemically combinedExaminer amine equivalent to one part of the free amine,

for every 2,000 to 14,000 parts of hydraulic cement constituent yieldsthe best results. Much smaller quantities result in a sacrifice of someof 25 the advantages of this invention; but much larger quantities, e.g. 25 times the minimum amount of any given amine required to yield theoptimum effect in concrete may actually defeat the purposes of theinvention and are therefore to be 30 avoided.

As previously indicated, the hydroxy-allwl amine may with substantiallyequivalent results either be mixed with the water, cement, andaggregates at the time the concrete is prepared or 35 first admixed withthe dry hydraulic cement before it is made into concrete. In the formercase it is convenient to dissolve the required quantity of the compoundin the gauging water. When the addition is made to the dry cement it isdesir- 40 able to add the amine in the form of one of its solid salts.For this purpose it is convenient to premix the finely powdered saltwith ground cement or other finely divided material, such as gypsum, ina, master batch before admixing it 45 m bulk of the hydraulic cementThis facilitates and insures a uniform distribution of the relativelyminute quantity of the active ingredient throughout the cement. Themaster batch may be g lded to the clinker beforeit entersthe tubg 5omill whefetiiorougfi n' din ends occur, or'it'may be mixed intb tfiefirially groim cement before it is packaged.

Concrete prepared from fixed quantities of cement, water, and aggregatesin accordance with 55 the general process of this invention possesses,in the wet condition, practically the same consistency, i. e. slump, andworkability, as exactly similar concrete which contains none of theherein described agents, but, in the hardened state, possesses asubstantially higher compressive strength than the latter. The extent ofthe'improvement in strength depends upon the cement and the mix employedas well as upon the particular amine or amine salt selected. Cementwhich has been ground to 'a somewhat superior degree of fineness is moreresponsive to the treatment than coarser material. The preferred amine,triethanol amine, generally affords a 15-25% improvement in the strengthof concrete made from ordinary Portland cement to a 1:2:4 mix. It willbe obvious to those skilled in the art that when it is desired to adhereto a given strength in the hardened concrete, this invention permits theuse of a leaner mix with the consequent well known economies than wouldotherwise be possible.

This invention permits the preparation, from the more usual type ofPortland cements, of high-early-strength cements which are equal orsuperior in strength to the commercial earlystrength Portland cementswhich are generally prepared by a double calcination procedure. For thispurpose the Portland cement clinker is ground in the presence of any ofour agents to a superior degree of fineness, e. g. until only 10% isretained by a standard ,325-mesh sieve; or the agent may be subsequ itlyadded to the properly ground cement. Early-strength cements preparedaccording to this general procedure are not only equal to commercialearly-strength materials in compressive strength characteristics butpossess the additional advantage that they evolve considerably less heatduring the hardening or strength-producing process than the usualearlystrength materials made by the double calcination procedure. Thisadvantage-leads to hardened concrete-S whicharemcre durable; for theless'er'volution of heat gives greater freedom from cracks, due tocooling and consequent contraction of the finally hardened concrete,particularly where large masses are involved.

The process and product of this invention may be used with advantagetogether with the common concrete admixtures such as diatomaceous earth,which is employed to improve the consistency of concrete, and heavymetal stearates, oleates, etc., which are added to concrete to make itshed water. These materials in no way interfere with the advantageousfunction of the herein described agents: each ingredient performs itsown advantageous function in the presence of the other.

What is claimed is:

1. That process for the preparation of concrete which includes mixinghydraulic cement, aggregates, and water in the presence of triethanolamine.

2. That process for the preparation of concrete which includes mixinghydraulic cement, aggregates, and water in the presence of diethanolamine.

3. That process for the preparation of concrete which includes mixinghydraulic cement, aggregates, and water in the presence oftriisopropanol amine.

" 4. As a new composition of matter dry hydraulic cement and a salt of ahydroxy-alkyl amine in intimate admixture therewith.

5. As a new composition of matter, dry hydraulic cement and a salt of anethanol amine in intimate admixture therewith.

6. As a new composition of matter, dry hydraulic cement and a salt oftriethanol amine in intimate admixture therewith.

7. As a new composition of matter, dry hydraulic cement and a salt oftri-isopropanol amine in intimate admixture therewith.

8. As a new composition of matter, dry hydraulic cement and ahydroxy-alkyl amine in intimate admixture therewith.

9. As a new composition of matter, dry hydraulic cement and an ethanolamine in intimate admixture therewith.

10. As a new composition of matter, dry hy-- Y draulic cement andtriethanol amine in intimate admixture therewith.

11. As a new composition of matter, hydraulic cement concrete containingtri-isopropanol amine and strengthened thereby.

12. As a new composition of matter, hydraulic cement concrete containingan ethanol amine and strengthened thereby.

13. As a new composition of matter, hydraulic cement concrete containingtriethanol amine and strengthened thereby.

14. As a new composition of matter, hydraulic cement concrete containingtri-isopropanol amine

